Restore DW_AT_abstract_origin for cross-unit call sites

PR debug/66503

gcc/ChangeLog:
	* debug.h (struct gcc_debug_hooks): Add a
	register_main_translation_unit hook.
	* debug.c (do_nothing_debug_hooks): Provide a function for this
	new hook.
	* dbxout.c (dbx_debug_hooks): Likewise.
	* sdbout.c (sdb_debug_hooks): Likewise.
	* vmsdbgout.c (vmsdbg_debug_hooks): Likewise.
	* dwarf2out.c (main_translation_unit): New global variable.
	(dwarf2out_register_main_translation_unit): New function
	implementing the new hook.
	(dwarf2_debug_hooks): Assign
	dwarf2out_register_main_translation_unit to this new hook.
	(dwarf2out_init): Associate any main translation unit to
	comp_unit_die ().
	* c/c-decl.c (pop_scope): Register the main translation unit
	through the new debug hook.
	* cp/decl.c (cxx_init_decl_processing): Likewise.

gcc/ada/ChangeLog:
	* gcc-interface/utils.c (get_global_context): Register the main
	translation unit through the new debug hook.

gcc/fortran/ChangeLog:
	* f95-lang.c (gfc_create_decls): Register the main translation
	unit through the new debug hook.

From-SVN: r224371

gcc/ChangeLog

+2015-06-11  Pierre-Marie de Rodat  <derodat@adacore.com>
+
+	* debug.h (struct gcc_debug_hooks): Add a
+	register_main_translation_unit hook.
+	* debug.c (do_nothing_debug_hooks): Provide a function for this
+	new hook.
+	* dbxout.c (dbx_debug_hooks): Likewise.
+	* sdbout.c (sdb_debug_hooks): Likewise.
+	* vmsdbgout.c (vmsdbg_debug_hooks): Likewise.
+	* dwarf2out.c (main_translation_unit): New global variable.
+	(dwarf2out_register_main_translation_unit): New function
+	implementing the new hook.
+	(dwarf2_debug_hooks): Assign
+	dwarf2out_register_main_translation_unit to this new hook.
+	(dwarf2out_init): Associate any main translation unit to
+	comp_unit_die ().
+	* c/c-decl.c (pop_scope): Register the main translation unit
+	through the new debug hook.
+        * cp/decl.c (cxx_init_decl_processing): Likewise.
+
 2015-06-11  Marek Polacek  <polacek@redhat.com>
 
 	* match.pd ((x & y) ^ (x | y) -> x ^ y): New pattern.

gcc/ada/ChangeLog

+2015-06-11  Pierre-Marie de Rodat  <derodat@adacore.com>
+
+	* gcc-interface/utils.c (get_global_context): Register the main
+	translation unit through the new debug hook.
+
 2015-06-09  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc-interface/misc.c: Remove duplicate include directives.

gcc/ada/gcc-interface/utils.c

@@ -667,7 +667,10 @@ static tree
 get_global_context (void)
 {
   if (!global_context)
-    global_context = build_translation_unit_decl (NULL_TREE);
+    {
+      global_context = build_translation_unit_decl (NULL_TREE);
+      debug_hooks->register_main_translation_unit (global_context);
+    }
   return global_context;
 }
 

gcc/c/c-decl.c

@@ -1196,6 +1196,7 @@ pop_scope (void)
     {
       tree file_decl = build_translation_unit_decl (NULL_TREE);
       context = file_decl;
+      debug_hooks->register_main_translation_unit (file_decl);
     }
   else
     context = block;

gcc/cp/decl.c

@@ -3831,6 +3831,8 @@ cxx_init_decl_processing (void)
   global_namespace = build_lang_decl (NAMESPACE_DECL, global_scope_name,
 				      void_type_node);
   DECL_CONTEXT (global_namespace) = build_translation_unit_decl (NULL_TREE);
+  debug_hooks->register_main_translation_unit
+    (DECL_CONTEXT (global_namespace));
   TREE_PUBLIC (global_namespace) = 1;
   begin_scope (sk_namespace, global_namespace);
 

gcc/dbxout.c

@@ -380,6 +380,7 @@ const struct gcc_debug_hooks dbx_debug_hooks =
   debug_nothing_tree,		         /* begin_function */
 #endif
   debug_nothing_int,		         /* end_function */
+  debug_nothing_tree,			 /* register_main_translation_unit */
   dbxout_function_decl,
   dbxout_early_global_decl,		 /* early_global_decl */
   dbxout_late_global_decl,		 /* late_global_decl */

gcc/debug.c

@@ -46,6 +46,7 @@ const struct gcc_debug_hooks do_nothing_debug_hooks =
   debug_nothing_int_charstar,	         /* end_epilogue */
   debug_nothing_tree,		         /* begin_function */
   debug_nothing_int,		         /* end_function */
+  debug_nothing_tree,		         /* register_main_translation_unit */
   debug_nothing_tree,		         /* function_decl */
   debug_nothing_tree,	         	 /* early_global_decl */
   debug_nothing_tree,	         	 /* late_global_decl */

gcc/debug.h

@@ -89,6 +89,10 @@ struct gcc_debug_hooks
   /* Record end of function.  LINE is highest line number in function.  */
   void (* end_function) (unsigned int line);
 
+  /* Register UNIT as the main translation unit.  Called from front-ends when
+     they create their main translation unit.  */
+  void (* register_main_translation_unit) (tree);
+
   /* Debug information for a function DECL.  This might include the
      function name (a symbol), its parameters, and the block that
      makes up the function's body, and the local variables of the

gcc/dwarf2out.c

@@ -2446,6 +2446,7 @@ static void dwarf2out_abstract_function (tree);
 static void dwarf2out_var_location (rtx_insn *);
 static void dwarf2out_begin_function (tree);
 static void dwarf2out_end_function (unsigned int);
+static void dwarf2out_register_main_translation_unit (tree unit);
 static void dwarf2out_set_name (tree, tree);
 
 /* The debug hooks structure.  */
@@ -2475,6 +2476,7 @@ const struct gcc_debug_hooks dwarf2_debug_hooks =
   dwarf2out_end_epilogue,
   dwarf2out_begin_function,
   dwarf2out_end_function,	/* end_function */
+  dwarf2out_register_main_translation_unit,
   dwarf2out_function_decl,	/* function_decl */
   dwarf2out_early_global_decl,
   dwarf2out_late_global_decl,
@@ -22505,6 +22507,26 @@ dwarf2out_end_function (unsigned int)
   maybe_at_text_label_p = false;
 }
 
+/* Temporary holder for dwarf2out_register_main_translation_unit.  Used to let
+   front-ends register a translation unit even before dwarf2out_init is
+   called.  */
+static tree main_translation_unit = NULL_TREE;
+
+/* Hook called by front-ends after they built their main translation unit.
+   Associate comp_unit_die to UNIT.  */
+
+static void
+dwarf2out_register_main_translation_unit (tree unit)
+{
+  gcc_assert (TREE_CODE (unit) == TRANSLATION_UNIT_DECL
+	      && main_translation_unit == NULL_TREE);
+  main_translation_unit = unit;
+  /* If dwarf2out_init has not been called yet, it will perform the association
+     itself looking at main_translation_unit.  */
+  if (decl_die_table != NULL)
+    equate_decl_number_to_die (unit, comp_unit_die ());
+}
+
 /* Add OPCODE+VAL as an entry at the end of the opcode array in TABLE.  */
 
 static void
@@ -23242,6 +23264,11 @@ dwarf2out_init (const char *filename ATTRIBUTE_UNUSED)
   /* Make sure the line number table for .text always exists.  */
   text_section_line_info = new_line_info_table ();
   text_section_line_info->end_label = text_end_label;
+
+  /* If front-ends already registered a main translation unit but we were not
+     ready to perform the association, do this now.  */
+  if (main_translation_unit != NULL_TREE)
+    equate_decl_number_to_die (main_translation_unit, comp_unit_die ());
 }
 
 /* Called before compile () starts outputtting functions, variables

gcc/fortran/ChangeLog

+2015-06-11  Pierre-Marie de Rodat  <derodat@adacore.com>
+
+	* f95-lang.c (gfc_create_decls): Register the main translation unit
+	through the new debug hook.
+
 2015-06-08  Andrew MacLeod  <amacleod@redhat.com>
 
 	* convert.c : Adjust include files.

gcc/fortran/f95-lang.c

@@ -204,6 +204,7 @@ gfc_create_decls (void)
 
   /* Build our translation-unit decl.  */
   current_translation_unit = build_translation_unit_decl (NULL_TREE);
+  debug_hooks->register_main_translation_unit (current_translation_unit);
 }
 
 

gcc/sdbout.c

@@ -296,6 +296,7 @@ const struct gcc_debug_hooks sdb_debug_hooks =
   sdbout_end_epilogue,		         /* end_epilogue */
   sdbout_begin_function,	         /* begin_function */
   sdbout_end_function,		         /* end_function */
+  debug_nothing_tree,		         /* register_main_translation_unit */
   debug_nothing_tree,		         /* function_decl */
   sdbout_early_global_decl,		 /* early_global_decl */
   sdbout_late_global_decl,		 /* late_global_decl */

gcc/vmsdbgout.c

@@ -194,6 +194,7 @@ const struct gcc_debug_hooks vmsdbg_debug_hooks
    vmsdbgout_end_epilogue,
    vmsdbgout_begin_function,
    vmsdbgout_end_function,
+   debug_nothing_tree,		  /* register_main_translation_unit */
    vmsdbgout_function_decl,
    vmsdbgout_early_global_decl,
    vmsdbgout_late_global_decl,